code: def test_property_background_opacity(prop):
      background_opacity = 0.5
      prop.background_opacity = background_opacity
      assert prop.background_opacity == background_opacity
      with pytest.raises(ValueError):
          prop.background_opacity = 2
  
imports: import os
  import numpy
  import pytest
  import pyvista
label_desc: Use image node_id 13 for calling a global function with example usage: test_property_background_opacity(prop) without return types